In the related art, ultraviolet ray curable ink, which is cured by emitted ultraviolet light, is used as offset sheet printing ink. In addition, ultraviolet ray curable resin is used as a sealing agent used for flat panel displays (FPDs) such as liquid crystal panels and organic electro luminescence (EL) panels. In general, an ultraviolet light emitting apparatus, which emits ultraviolet light, is used to cure the ultraviolet ray curable ink or the ultraviolet ray curable resin, and particularly, a light emitting apparatus having multiple light emitting elements, which are arranged on a substrate so as to be directed toward an irradiation region is used to perform the offset sheet printing or manufacture the FPDs because it is necessary to emit the ultraviolet light with high irradiation intensity toward the irradiation region having a wide width and a rectangular shape (for example, see Patent Document 1).
The ultraviolet light emitting apparatus disclosed in Patent Document 1 has a base plate on which multiple light emitting elements are two-dimensionally disposed, a reflection tube (mirror units) which is disposed to surround the base plate and guides ultraviolet light emitted from the light emitting elements, and a cooling unit which cools the base plate. Further, the ultraviolet light emitting apparatus is configured to obtain a uniform irradiation distribution in the irradiation region by mixing the ultraviolet light by using the mirror units.